sedimentary

Chert with Epidote and Jasper inclusions

SiO2 (Silicon Dioxide) with Ca2(Al, Fe)3(SiO4)3(OH) inclusions

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale); Color: White, green, and reddish-brown; Luster: Waxy to vitreous; Structure: Microcrystalline; Cleavage: None (conchoidal fracture).

Hardness: 6
Color: White, green, and reddish-brown
Luster: Waxy to vitreous

Identified June 16, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: White, green, and reddish-brown; Luster: Waxy to vitreous; Structure: Microcrystalline; Cleavage: None (conchoidal fracture).

Formation & geological history

Formed via the accumulation of silica-rich microfossils or chemical precipitation in marine environments, with inclusion of iron-rich jasper and green epidote through hydrothermal activity or metamorphism.

Uses & applications

Used primarily for lapidary work, decorative cabochons, and as a collector's specimen. Historically used for stone tools due to its fracture pattern.

Geological facts

This specimen appears to be a 'river-worn' cobble, likely from a high-energy environment like a stream bed which has naturally tumbled and smoothed the surface. It shows a complex mix of various silicate minerals.

Field identification & locations

Identify in the field by its waxy luster, smoothness, and the ability to scratch glass. Commonly found in gravel deposits, river beds, and coastal areas in regions with tectonic activity like the Pacific Northwest.